Photodissociation of 1,3,5-Triazine: An Ab Initio and RRKM Study

The ab initio/Rice-Ramsperger-Kassel-Marcus (RRKM) approach has been applied to investigate the photodissociation mechanism of 1,3,5-triazine at different wavelengths of the absorbed photon. Reaction pathways leading to various decomposition products have been mapped out at the G3(MP2,CC)//B3LYP level, and then the RRKM and microcanonical variational transition state theories have been applied to compute rate constants for individual reaction steps. Relative product yields (branching ratios) for the dissociation products have been calculated using the steady-state approach. The results show that, after being excited by 275, 248, or 193 nm photons, the triazine molecule isomerizes to an opened-ring structure on the first singlet excited-state potential energy surface (PES), which is followed by relaxation into the ground electronic state via internal conversion. On the contrary, excitation by 285 and 295 nm photons cannot initiate the ring-opening reaction on the excited-state PES, and the molecule relaxes into the energized ring isomer in the ground electronic state. The dissociation reaction starting from the ring isomer is calculated to have branching ratios of various reaction channels significantly different from those for the reaction initiating from the opened-ring structure. The existence of two distinct mechanisms of 1,3,5-triazine photodissociation can explain the inconsistency in the translational energy distributions of HCN moieties at different wavelengths observed experimentally.

Familial aggregation of metabolic syndrome among the Chinese: report from the Chin-Shan community family study

Genetic study on metabolic syndrome is a great challenge, due to its complex traits and the pleiotropic manifestation of atherosclerosis. Familial aggregation and recurrence risk ratio can provide the insight of possible genetic mechanism. The Chin-Shan community family study was based on adolescent probands and their relatives (1356 subjects) who were recruited from one junior high school in the community. Structured questionnaires and biochemical measures were obtained in standard procedures. Definition of metabolic syndrome was followed using the criteria defined by the third adult treatment panel, with a modification of the criteria for adolescent and Asian population. Grandmothers had the highest frequencies (70%) in metabolic syndrome and various atherosclerotic risks. Three factors were found and thus explained 68% of the overall variance. Estimated heritability was the highest in LDL and cholesterol factor (0.36 and 0.40), then blood pressure/obesity factor (0.27), and insulin resistance/dyslipidemia (0.27). Recurrence risk ratio among siblings was 2.95 (95% confidence interval [CI]: 1.39-6.26). The adjusted odds ratio (OR) of proband's metabolic syndrome status was 1.99 (95% CI: 1.08-3.66). The adjusted odds ratios for the three factors for predicting metabolic syndrome were all significant, with highest risk in blood pressure/obesity factor (OR: 1.27, CI: 1.22-1.33), then insulin resistance/dyslipidemia (OR: 1.29, CI: 1.16-1.23). This study demonstrated clearly familial aggregation and recurrence risk ratio of metabolic syndrome and components among the general ethnic Chinese population in Taiwan.

Martial arts as sport and therapy

The term Martial Arts is often used as general phrase to describe many of the combat arts, which have developed in eastern cultures over the past millennium. This paper reviews the Martial Arts from the original context of a trio of life skills. This trio includes the healing arts such as acupuncture, the self-exploration arts such as yoga, and the vital life skills such as meditation. As Martial Arts suggests the waging of combat, the origins of the most common combat arts are reviewed, with an overview of the difference between the hard and the soft styles. The arts developed not only in the eastern, but also in all parts of the world, with references of these types of combats arts in the writings of the ancient Egyptians and Greeks. In modern times, the combat arts are performed for both exercise and sport. A review of the injuries that occur, and the health benefits that might be expected are discussed. A review of the medical literature that demonstrates some of these health benefits is included, with Tai Chi Chuan as the most studied of these. The health benefits discussed include strengthen and self-efficacy of the elderly, reduced falls, increased exercise capacity, and benefits to the immune system and autonomic nervous system. The paper emphasized the breadth of the Martial Arts and the import of these to the sports and health community.

An automatic method for identifying appropriate gradient magnitude for 3D boundary detection of confocal image stacks

Gradients play an important role in 2D image processing. Many edge detection algorithms are gradient-based. We are interested in 3D boundary detection which can be considered as an extension of 2D edge detection in 3D space. In this paper, an algorithm to automatically and quantitatively measure the suitability of gradient magnitudes in detection of 3D boundary points of confocal image stacks is presented. A Measurement Function is defined to evaluate the suitability of each gradient magnitude chosen to be the threshold for 3D boundary detection. The application of Gauss's Divergence Theorem provides a solution to calculate the Measurement Function numerically. The gradient magnitude at which the maximum of the Measurement Function is achieved can be utilized as the most appropriate threshold for gradient-based boundary detection and other operations like volume visualization.

Improved colonoscopy success rate with a distally attached mucosectomy cap

BACKGROUND AND STUDY AIMS

Although colonoscopy is a well-established procedure, various technical difficulties may cause failure. This report describes experience with cap-assisted colonoscopy (CAC), a technique in which a mucosectomy cap is attached to the end of colonoscope in order to improve the success rate.

PATIENTS AND METHODS

From January 2003 to May 2005, CAC was used in consecutive patients with difficult colonoscopy procedures, which were defined firstly as failure to pass through the sigmoid colon after 20 min of examination, or secondly as failure to reach the cecum at the end of the procedure. Patients with prior colonic surgery, poor bowel preparation, distal colonic stricture, or obstructing tumors were excluded. The results with the CAC method were reviewed retrospectively.

RESULTS

A total of 100 patients met the criteria for difficult colonoscopy during the study period. When CAC was used to repeat the procedure, cecal and terminal ileal intubation could then be achieved in 94 and 70 patients, respectively. In the remaining six patients in whom cecal intubation failed, one failure was due to a tumor obstruction at the splenic flexure.

CONCLUSIONS

CAC can be used as a rescue method to improve the success rate of colonoscopy when failure is encountered.

Ab initio and RRKM study of photodissociation of azulene cation

The ab initio/Rice-Ramsperger-Kassel-Marcus (RRKM) approach has been applied to investigate the photodissociation mechanism of the azulene cation at different values of the photon energy. Reaction pathways leading to various decomposition products have been mapped out at the G3(MP2,CC)//B3LYP level and then the RRKM and microcanonical variational transition state theories have been applied to compute rate constants for individual reaction steps. Relative product yields (branching ratios) for the dissociation products have been calculated using the steady-state approach. The results show that a photoexcited azulene cation can readily isomerize to a naphthalene cation. The major dissociation channels are elimination of atomic hydrogen, an H2 molecule, and acetylene. The branching ratio of the H elimination channel decreases with an increase of the photon energy. The branching ratio of the acetylene elimination as well as that of the H2 elimination rise as the photon energy increases. The main C8H6+ fragment at all photon energies considered is a pentalene cation, and its yield decreases slightly with increasing excitation energy, whereas the branching ratios of the other C8H6+ fragments, phenylacetylene and benzocyclobutadiene cations, grow.

Accuracy of endoscopic ultrasonography in diagnosing ascites and predicting peritoneal metastases in gastric cancer patients

BACKGROUND

Preoperative diagnosis of peritoneal metastases (PM) is difficult in patients with gastric cancer (GC).

AIMS

To assess the accuracy of endoscopic ultrasonography (EUS) in diagnosing ascites and its predictability for the presence of PM in GC patients.

SUBJECTS

Consecutive patients with newly diagnosed GC from 1998 to 2004 were studied.

METHODS

All patients underwent EUS, ultrasound (US), and computed tomography (CT) scan for preoperative staging and the presence of ascites. The results were compared with operative findings. The diagnosis of PM was confirmed by histopathology or peritoneal fluid cytology.

RESULTS

A total of 301 patients were recruited and in 250 patients the presence of ascites (n = 93) and PM (n = 71) were confirmed. EUS was more sensitive (87.1%) than combined US and CT scan examinations (16.1%) and operative findings (laparoscopy or laparotomy) (40.9%) in diagnosing ascites. Sensitivity, specificity, positive and negative predictive values, and accuracy for predicting the presence of PM were 73%, 84%, 64%, 89%, and 81% by EUS; 18%, 99%, 87%, 75%, and 76% by combining US and CT scan; and 77%, 94%, 83%, 91%, and 89% by operative findings, respectively. In multivariate logistic regression analysis, EUS detected ascites was the only significant independent predictor for the presence of PM (p<0.001; odds ratio 4.7 (95% confidence interval 2.0-11.2)).

CONCLUSION

EUS is a sensitive method for diagnosing ascites which is an important predictive factor for the presence of PM in GC patients.

Photodissociation of azulene at 193 nm: ab initio and RRKM study

The ab initio/Rice-Ramsperger-Kassel-Marcus (RRKM) approach has been applied to investigate the photodissociation mechanism of azulene at 6.4 eV (the laser wavelength of 193 nm) upon absorption of one UV photon followed by internal conversion into the ground electronic state. Reaction pathways leading to various decomposition products have been mapped out at the G3(MP2,CC)//B3LYP level and then the RRKM and microcanonical variational transition state theories have been applied to compute rate constants for individual reaction steps. Relative product yields (branching ratios) for the dissociation products have been calculated using the steady-state approach. The results show that photoexcited azulene can readily isomerize to naphthalene and the major dissociation channel is elimination of an H-atom from naphthalene. The branching ratio of this channel decreases with an increase of the photon energy. Acetylene elimination is the second probable reaction channel and its branching ratio rises as the photon energy increases. The main C8H6 fragments at 193 nm are phenylacetylene and pentalene and the yield of the latter grows fast with the increasing excitation energy.

A double-blind comparison of the efficacy and tolerability of telmisartan 40-80 mg vs. losartan 50-100 mg in Taiwanese hypertensive patients

A multicentre, randomised, double-blind, double-dummy, parallel-group, dose-titration study was conducted to determine the efficacy and tolerability of telmisartan 40-80 mg once daily compared with losartan 50-100 mg once daily in 180 Taiwanese patients with mild-to-moderate essential hypertension. After an initial 2-week placebo run-in phase, patients were randomised in a double-blind, double-dummy fashion to receive either telmisartan 40 mg or losartan 50 mg. If blood pressure control (diastolic blood pressure [DBP] <90 mmHg or > or = 10 mmHg reduction in DBP) was achieved after 4 weeks, the dose was maintained for the second 4 weeks of the active treatment phase; if not, the dose was doubled to telmisartan 80 mg or losartan 100 mg, respectively, for the second 4 weeks of double-blind treatment. Telmisartan 40-80 mg (n = 86) was as effective as losartan 50-100 mg (n = 90) in reducing trough seated DBP (11.1 vs. 8.7 mmHg, p = 0.144), and was significantly more effective than losartan in reducing trough seated systolic blood pressure (SBP) (22.1 vs. 16.5 mmHg, p = 0.032) and standing SBP (21.0 vs. 16.3 mmHg, p = 0.033). Significantly fewer patients treated with telmisartan than those treated with losartan required uptitration after 4 weeks' treatment (32.6% vs. 61.5%, p = 0.001). Both telmisartan and losartan were well tolerated.

Comparison of breath-hold 2D phase-contrast with non breath-hold cine phase-contrast MRA in the assessment of azygos venous blood flow in portal hypertension

Azygos venous blood flow as an index of blood flow through the gastroesophageal collaterals and varices is of value in the prediction of gastrointestinal bleeding. Measurement of azygos venous blood flow has been achieved by non breath-hold (NBH) cine phase-contrast magnetic resonance imaging. The objective of this study was to compare the faster breath-hold (BH) phase-contrast technique with the standard (NBH) cine phase-contrast technique in the measurement of azygos blood flow. Thirty-two cirrhotic patients with esophageal varices were examined by magnetic resonance imaging using a BH technique and a NBH cine phase-contrast technique to measure the flow velocity, flow volume and calibre of the azygos vein at the mid-right atrial level. The flow values were obtained on the velocity image of the phase-contrast study. Values obtained from the two methods were evaluated statistically for the strength and significance of correlation by the Pearson test. Measurement by the BH method performed at full-inspiration as well as end-expiration was also obtained in 15 healthy volunteers. The breath-hold phase-contrast method has significant but weak correlation with non BH cine phase-contrast method in the measurement of azygos venous blood flow volume (r = 0.55, p < 0.01) and flow velocity (r = 0.43, p = 0.01). However, the calibre of the azygos vein gave a strong correlation in these two methods (0.82). In the subgroup of patients whose azygos blood flow velocity was greater than 7.4 cm/s, the correlation of azygos blood flow volume is strong (r = 0.80, p < 0.01). The azygos vein calibre remains highly correlated between the BH and NBH method, in both high flow velocity (r = 0.73) and low flow velocity (r = 0.83) groups. Breath-hold sequence leads to higher values for flow velocity and flow volume in the cirrhotic patients and also the control group. In patients with portal hypertension, BH 2D phase-contrast (PC) magnetic resonance angiography (MRA) could give a comparable estimation of the calibre of the azygos vein as the NBH 2D cine PC MRA but not for azygos flow volume. In patients with high azygos flow velocity, the strong correlation in flow volume between the BH and NBH method suggests that the BH method may be a time-saving alternative to the NBH method.

Quality of life in Chinese patients with inflammatory bowel disease: validation of the Chinese translation of the Inflammatory Bowel Disease Questionnaire

BACKGROUND

Health-related quality of life is an important outcome measure in inflammatory bowel disease. The Inflammatory Bowel Disease Questionnaire is a quality of life questionnaire that has not been validated previously in Chinese patients with inflammatory bowel disease.

AIM

To develop and validate a Chinese translation of the Inflammatory Bowel Disease Questionnaire, specifically determining its construct validity, discriminant ability, reliability and sensitivity to change.

METHODS

We developed a Chinese version of the Inflammatory Bowel Disease Questionnaire. Chinese patients with Crohn's disease and ulcerative colitis completed the Chinese Inflammatory Bowel Disease Questionnaire and visual analogue scales measuring systemic, social, bowel and emotional well-being. Patients also completed a validated Chinese SF-36 generic quality of life questionnaire, the Crohn's disease activity index or the clinical activity index for ulcerative colitis.

RESULTS

One hundred and thirty-five patients (59 with Crohn's disease and 76 with ulcerative colitis) were enrolled, 99 of whom also completed the Chinese Inflammatory Bowel Disease Questionnaire for a second time. The Chinese Inflammatory Bowel Disease Questionnaire correlated well with the SF-36 for all four domains (Spearman: r = 0.55-0.80), the Crohn's disease activity index (r = -0.62-0.72) and the clinical activity index for ulcerative colitis (r = -0.44-0.68), as well as with the visual analogue scales. The Chinese Inflammatory Bowel Disease Questionnaire accurately distinguished between active and inactive disease. Test-re-test reliability showed excellent intra-class correlation (0.76-0.92; all P < 0.001). The Chinese Inflammatory Bowel Disease Questionnaire was also sensitive to changes in disease activity (P < 0.05).

CONCLUSION

The Chinese Inflammatory Bowel Disease Questionnaire is a valid and reliable test that correlates well with the patients' subjective well-being and clinical disease activity.

Diagnosis of gastroesophageal varices and portal collateral venous abnormalities by endosonography in cirrhotic patients

BACKGROUND AND STUDY AIMS

The role of endosonography (EUS) in the management of portal hypertension is not well defined. We aimed to study the use of a new generation video-echo endoscope in the diagnosis of gastroesophageal varices (GEV) and extraluminal venous abnormalities in cirrhotic patients.

PATIENTS AND METHODS

Cirrhotic patients were studied by echo endoscopy to assess esophageal varices endoscopically, and gastric varices and extraluminal venous abnormalities sonographically. The results were compared with esophagogastroduodenoscopy (EGD) examination. Dyspeptic patients served as controls.

RESULTS

A total of 52 cirrhotic and 166 dyspeptic patients were studied. EUS identified esophageal varices (EV) endoscopically in 28 patients (53.8 %), which showed a good correlation with EGD findings (r = 0.855, P < 0.001). The red color sign and portal hypertensive gastropathy were diagnosed in six and seven patients, respectively, by both methods. EUS detected gastric varices sonographically in 16 patients (30.8 %), compared with detection in nine patients by EGD. Extraluminal venous abnormalities were detected in 48 cirrhotic patients (92 %) and in only nine dyspeptic patients (5.4 %) (P < 0.001). The size of extraluminal adventitial venous dilatation was significantly correlated with the severity of GEV and cirrhosis (P < 0.001). Perforating veins were identified in all patients with GEV.

CONCLUSION

The new generation video-echo endoscope could be used as a single investigation in assessing both the intraluminal GEV and extraluminal venous abnormalities in cirrhotic patients. It may improve the management of patients with portal hypertension.

A combined crossed molecular beam and ab initio investigation of C2 and C3 elementary reactions with unsaturated hydrocarbons--pathways to hydrogen deficient hydrocarbon radicals in combustion flames

Crossed molecular beam experiments on dicarbon and tricarbon reactions with unsaturated hydrocarbons acetylene, methylacetylene, and ethylene were performed to investigate the dynamics of channels leading to hydrogen-deficient hydrocarbon radicals. In the light of the results of new ab initio calculations, the experimental data suggest that these reactions are governed by an initial addition of C2/C3 to the pi molecular orbitals forming highly unsaturated cyclic structures. These intermediates are connected via various transition states and are suggested to ring open to chain isomers which decompose predominantly by displacement of atomic hydrogen, forming C4H, C5H, HCCCCCH2, HCCCCCCH3, H2CCCCH and H2CCCCCH. The C2(1 sigma g+) + C2H4 reaction has no entrance barrier and the channel leading to the H2CCCCH product is strongly exothermic. This is in strong contrast with the C3(1 sigma g+) + C2H4 reaction as this is characterized by a 26.4 kJ mol-1 threshold to form a HCCCCCH2 isomer. Analogous to the behavior with ethylene, preliminary results on the reactions of C2 and C3 with C2H2 and CH3CCH showed the H-displacement channels of these systems to share many similarities such as the absence/presence of an entrance barrier and the reaction mechanism. The explicit identification of the C2/C3 vs. hydrogen displacement demonstrates that hydrogen-deficient hydrocarbon radicals can be formed easily in environments like those of combustion processes. Our work is a first step towards a systematic database of the intermediates and the reaction products which are involved in this important class of reactions. These findings should be included in future models of PAH and soot formation in combustion flames.

Effect of Helicobacter pylori eradication on oesophageal acid exposure in patients with reflux oesophagitis

BACKGROUND

The effect of Helicobacter pylori eradication on reflux oesophagitis is unclear.

AIM

To study the effect of H. pylori eradication on oesophageal acid exposure and disease severity in patients with reflux oesophagitis.

METHODS

Patients with reflux oesophagitis and H. pylori infection were recruited for 24-h oesophageal pH-metry. They were then randomly assigned to receive either treatment for H. pylori eradication (1-week omeprazole-based triple therapy, followed by 7-week omeprazole) or omeprazole alone (8-week omeprazole). Uninfected patients were recruited as controls. Endoscopy, pH monitoring and symptom assessment were repeated at 26 weeks.

RESULTS

Forty patients (25 H. pylori-positive and 15 uninfected) with erosive oesophagitis were studied. Fourteen were randomized to receive treatment for H. pylori eradication and 11 to receive omeprazole alone. There was no difference in the percentage of time the oesophageal pH < 4 before and 26 weeks after treatment among the three groups. However, the percentage of time the oesophageal pH < 2 (P=0.01) and pH < 3 (P=0.02) was significantly increased in patients receiving treatment for H. pylori eradication. Three (21%) patients in the group receiving treatment for H. pylori eradication had worsening of reflux oesophagitis.

CONCLUSIONS

H. pylori eradication increases oesophageal acid exposure and may adversely affect the clinical course of reflux disease in a subset of patients.

Suppression of collagen-induced arthritis in rats by continuous administration of dae-bang-poong-tang (da-fang-feng-tang)

Although dae-bang-poong-tang (an herbal formula of 15 herbs)-treated rats exhibited a mild inflammation, the significant histological changes including a marked infiltration of inflammatory cells in the synovium and damaged articular cartilages were not observed. The staining abilities of the cartilage such as periodic acid Schiff s reaction in the interterritorial matrix of hyaline cartilage, alcian blue and aldehyde fuchsin staining in the capsule of chondrocytes and in the interterritorial matrix of articular cartilage and Con A, sWGA and BSL-1 affinities of chondrocytes tended to decrease in the rats with collagen-induced arthritis compared with normal rats. Decreased stainabilities and affinities were almost recovered in the dae-bang-poong-tang-treated rats. In the collagen-induced rats, iNOS expression in the synovial lining cells and subsynovial tissue were significantly increased and numerous strong immunoreactive cells were demonstrated in the subsynovial tissue. Somewhat decreased immunoreaction of iNOS was shown in the synovial lining cells and subsynovial tissue of dae-bang-poong-tang-treated rats. It was concluded that dae-bang-poong-tang showed a notable protection against histological changes and histochemical staining, and it acted as an inhibitor of iNOS expression. Dae-bang-poong-tang may be used as a complementary therapeutic agent to alleviate the rheumatoid arthritis.

Single-particle mass spectrometry of polystyrene microspheres and diamond nanocrystals

High-resolution mass spectra of single submicrometer-sized particles are obtained using an electrospray ionization source in combination with an audio frequency quadrupole ion-trap mass spectrometer. Distinct from conventional methods, light scattering from a continuous Ar-ion laser is detected for particles ejected out of the ion trap. Typically, 10 particles are being trapped and interrogated in each measurement. With the audio frequency ion trap operated in a mass-selective instability mode, analysis of the particles reveals that they all differ in mass-to-charge ratio (m/z), and the individual peak in the observed mass spectrum is essentially derived from one single particle. A histogram of the spectra acquired in 10(2) repetitions of the experiment is equivalent to the single spectrum that would be observed when an ion ensemble of 10(3) particles is analyzed simultaneously using the single-particle mass spectrometer (SPMS). To calibrate such single-particle mass spectra, secular frequencies of the oscillatory motions of the individual particle within the trap are measured, and the trap parameter qz at the point of ejection is determined. A mass resolution exceeding 10(4) can readily be achieved in the absence of ion ensemble effect. We demonstrate in this work that the SPMS not only allows investigations of monodisperse polystyrene microspheres, but also is capable of detecting diamond nanoparticles with a nominal diameter of 100 nm, as well.

Peripheral blood cells among community residents living near nuclear power plants

Information about hematopoieses as a result of exposure to very low levels of radiation is scarce. To investigate the human hematopoietic effect of very low level radiation exposure, measurements of peripheral blood components were performed among 3602 men and women, aged 35 and above, living in a community near two nuclear power installations in Chinshan, Taiwan. The radiation level that each individual was exposed to was represented by a surrogate level, '1/D2(1i) + 1/D2(2i)', a transformed distance from each individual's residence to the two power plants D1 and D2. In addition to comparing average hematology measurements, multiple regression analyses were done to include age, gender, smoking, drinking status and the surrogate radiation exposure level as independent variables. Univariate and bivariate analyses showed that the hematology measurements had significant associations with age, gender, smoking or drinking. The multiple regression analyses revealed that significant positive associations with '1/D2(1i) + 1/D2(2i)' were found for hemoglobin, hematocrit, platelet, white blood cell and red blood cell. The platelet count might increase for 208.7 x 10(3)/microl if the exposure from the nuclear plants increased by one exposure unit. This type of association implies that those who lived closer to the nuclear power installation had a higher blood cell count; we suspect that this could be a type of radiation hormesis.

Influence of CETP gene variation on plasma lipid levels and coronary heart disease: a survey in Taiwan

Cholesteryl ester transfer protein (CETP) transfers cholesteryl ester from high-density lipoprotein (HDL) to very low-density lipoprotein (VLDL), low-density lipoprotein (LDL) and chylomicron in exchange for triglycerides. Two CETP genetic variation and four polymorphisms are investigated by polymerase chain reaction (PCR) and restriction enzyme digestion in a population of Taiwan. The results show that a very rare variation frequency is found for CETP intron 14 splice site G-->A change. The population shows a predominant 405Ile allele (61%), 442Asp (97.7%), intron 1Taq1B(+) G allele (52%), intron 8 Msp1(-) A allele (89%) and intron 9 EcoN1(-) T allele (59.2%) in the control group. Patients with coronary heart disease (CHD) have more CETP EcoN1(+/+) GG genotype (25.3%) than the controls (13.6%) (P=0.049). The intron 1 Taq1B(-) A allele is associated with a high HDL cholesterol and apoA1 level, the EcoN1(+) G allele with a low apoA1 level and the 442Gly with both high total cholesterol and LDL cholesterol levels. Paradoxically, the 442Gly is also present with a higher frequency (5.2%) in HDL cholesterol > or =65 mg/dl group than that in the general population (2.3%) (P=0.04).